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The presence of dense non-aqueous phase liquid (DNAPL) in fractured-aquifer systems introduces remediation challenges that are widely recognized, yet the DNAPL dissolution kinetics in these fractured systems has not been studied in detail. In this research, the dissolution of tetrachloroethylene (PCE) DNAPL during aqueous groundwater flow is experimentally evaluated using a three-dimensional bench-scale fracture network constructed using nine low-porosity sandstone blocks (fracture network). Seven dissolution experiments were conducted to identify and quantify the fundamental processes controlling and influencing DNAPL dissolution mass transfer rates in the experimental fracture network. The underlying hypothesis of this research is the assertion that DNAPL dissolution in the experimental fracture network varies as a function of DNAPL saturation, DNAPL interfacial area and fracture network properties such as dispersivity, linear velocity, mass balance aperture, and frictional loss aperture. Effluent aqueous phase PCE concentrations, collected during the seven dissolution experiments, were used to quantify the dissolution mass-transfer rates. All experimentally derived mass transfer rates were evaluated against system properties to determine the primary factors controlling dissolution: DNAPL-water interfacial area, Reynolds number (lumped parameter that includes velocity and liquid properties) and the fracture network properties. Preliminary results indicate a positively correlated relationship exists between the bulk mass transfer rate with DNAPL-water interfacial area and DNAPL saturation in the experimental fracture network. The results of the fracture network dissolution experiments were statistically evaluated against the results of six single-fracture dissolution experiments from the literature.
